[meteorite-list] Black Mats

From: E.P. Grondine <epgrondine_at_meteoritecentral.com>
Date: Sun, 26 Aug 2007 10:28:37 -0700 (PDT)
Message-ID: <586016.20271.qm_at_web36911.mail.mud.yahoo.com>

Hi Paul -

Thanks for the backgrounder on the "black mats".
Amazing - not one personal insult in it!!!!

Clearly, the black mats are too common and from too
many dates to make the extraction of spherules for
commercial purposes possible. Oh well... damn... that
still leaves the folks at home doing rooftop spherule
collections with pans for free... and it still leaves
those strata in Italy as a handy source for KT
spherules... I wonder if super magnets would work on
separating spherules out of the Tunguska soils...

As was the case with Hibbens and the deposits along
Alaskan rivers, the black mats that will be of
interest in terms of the holocene start impacts will
be the ones between 10,900 BCE and say 8,350 BCE -
they should have worked as traps for atmospheric
spherules, just as the ice cores do. Given the
ordinary occurence of spherules, the HIWG is going to
have rough slog, unless their mats have some more
extraordinary materials in them.

What's interesting here are some of the dates you
cited from Quade:

"These black mats are related to elevated water tables
and increased spring activity and cluster in age at
9,500 to 10,500 14C yr B.P."

in other words say roughly 8,500 BCE to 7,500 BCE -
this agrees better with the Remington Quarry end of
use dates, around 8,350 BCE, and differs from the
Holocene Impact Working Group's announced 10,900 BCE
date. Good dates are necessary for tracking this back
to Comet Encke's orbit...

I suppose that in the future every excavation team
will be at least preserving better soil samples, even
if they can not afford analysis at the time of
excavation.
And yes, it might be a good idea for you to do a
microscopic examination of your soil samples from
Lubbock.

I still think that there was a substantial alteration
of the North Pacific Current, which occurred as the
Lenpewak remembered. But how? The Sakhalinda crater
seems to be out of the running for now, but what the
hell happened in Beringia?

Oh well, the new USGS coastal cores will be along
shortly... along with the Canadian west coast
underwater excavations...

E.P. Grondine
Man and Impact in the Americas
"Geopoetry!" rages Paul



       
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Received on Sun 26 Aug 2007 01:28:37 PM PDT